1. Field of the Invention
The present invention relates to a method for providing traffic information to a traveler concerning one or more specific sections of a route.
2. Description of the Related Art
Traffic advisory messages are known as the dominant form of delivery for up-to-date traffic information. The traffic advisory message is a data file which gives information concerning a traffic flow situation such as the location, extent, type, and possibly other properties, the traffic flow situation typically being a situation in which the flow of traffic is being hindered in some way. The traffic advisory message may be presented to recipient in various ways, e.g., it can be read over the radio, called up via a menu-controlled voice dialog system, noted while performing a navigation task, viewed in the form of text on display unit, or using other forms of communication.
An important criterion for the quality of the traffic information composed in the form of an advisory is its currency. The longer the period of time which passes between the moment at which the advisory is valid and the moment at which it is relevant to the recipient, the greater the probability that all of the details of the traffic advisory will no longer accurately reflect the situation which the user will actually find at the location in question if he actually goes there after having learned of the content of the advisory.
There are five different factors which determine this period of time, referred to in the following as the “advisory delay”. The four most important ones are listed here:
1. the gap of time between the time when the event occurs on the highway and the time when it is observed for the first time and reported to a central location;
2. the time it takes for a suitable traffic advisory to be composed at the central location;
3. the time required for the dissemination of the advisories according to certain procedures for dissemination, e.g., because the procedures are periodic; and
4. the usually false assumption of the recipient that the traffic advisory which has reached them continues to be valid without change until the recipient actually reaches the location of the reported event.
The delays in the delivery of the advisory message acquire a subjective and individual component especially as a result of the fourth of the above-listed factors. The existing dissemination channels and terminals are designed to receive traffic information in the form of advisory messages.